1 / 41

Model Based Chemical Analyses

Model Based Chemical Analyses. Model Based Analyses.

laith-welch
Download Presentation

Model Based Chemical Analyses

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Model Based Chemical Analyses

  2. Model Based Analyses The very rigid constraints of a chemical model form a framework within which the fit is confined and which results in a robust analysis, in model-free analysis, this framework is dramatically wider and looser and these methods suffer gradually from a sever lack of robustness. It must be remembered, however, that the choice of the wrong model necessarily results in the rung analysis and wrong resulting parameters.

  3. k A B d[A] = -k [A] dt [A]0=1 k=0.2 Simple first order kinetics [A] = [A]0 exp (-kt) [B] = [A]0 (1 - exp (-kt))

  4. Selective region for B Selective region for A

  5. Univariate data Al=440 = eA [A]0 exp (-kt) + r Al=540 = eB [A]0 (1 - exp (-kt)) + r

  6. How one can determine the parameters of the model? ^ Al=440 = eA [A]0 exp (-kt) + r Suppose eA=1.3 & k=0.25

  7. How one can determine the parameters of the model? ^ Al=440 = eA [A]0 exp (-kt) + r Suppose eA=1.3 & k=0.25 RSS = S (ri2) RSS =0.15

  8. How one can determine the parameters of the model? ^ Al=440 = eA [A]0 exp (-kt) + r Suppose eA=1.0 & k=0.20 RSS =1.42 × 10-5

  9. 0.5 < eA < 1.5 & 0.1 < k < 0.3

  10. 0.5 < eA < 1.5 & 0.1 < k < 0.3

  11. Direct Fitting Kinfit1.m

  12. Data which should be fitted

  13. Data set file

  14. Calling kinfit1 function

  15. ? Modify the kinfit1 function for fitting a kinetic curve which is selective for product.

  16. eA Linear Parameters Al=440 = eA [A]0 exp (-kt) + r = + y x eA = + r r= f (k) eA = (yTy)-1 yT x

  17. Kinfit2.m

  18. ? Investigate the effects of non-correct value of initial concentration on the results of analysis.

  19. Selective multivariate data Al1 = eA1 {[A]0 exp (-kt)} + rl1 eA1 = + eA1 eA2 Al2 = eA2 {[A]0 exp (-kt)} + rl2 = + eA2 = +

  20. Selective region for A Selective region for A

  21. In the absence of selectivity

  22. k A B eA eB At each non-selective wavelength A = eA [A] + eB [B] = eA eB = +

  23. k A B eA eA eA eA eA eA eB eB eB eB eB eB At each non-selective region = C = f(k) A = C ET + R R = A – C C+ A R = f(k)

  24. ? Is there any limitation in numbers of wavelengths?

  25. Kinfit3.m

  26. ? How one can find the error of calculated parameter?

More Related